Cylinder lock operable with two keys

ABSTRACT

A CYLINDER LOCK IS DISCLOSED WITH TURNABLE LOCKING DISKS AND OPERABLE WITH TWO DIFFERENT KEYS. ONE KEY CAN BE USED TO OPERATE THE CLOCKWISE ONLY AND THE OTHER KEY TO OPERATE THE LOCK COUNTERCLOCKWISE ONLY. THE FUNCTION OF THE LOCK IS BASED IN THE PRINCIPLE THAT THE LOCKING DISKS CAN MOVE WITHIN A LIMITED ANGLE WITH RESPECT TO THE CYLINDER OF THE LOCK, THAT IS BETWEEN TWO END POSITIONS, AND THAT THE ONE KEY STARTS IS OPERATION MOVEMENT WITH THE LOCKING DISKS IN ONE END POSITION AND THE OTHER KEY WITH THE LOCKING DISKS IN THE OPPOSITE END POSITION.

Nov. 23, 1971 R. KOSKINEN ET AL 3,621,689

CYLINDER LOCK OPERABLE WITH TWO KEYS Filed May 26, 1969 United States Patent U.S. Ci. 70366 8 Claims ABSTRACT OF THE DISCLOSURE A cylinder lock is disclosed with turnable locking disks and operable with two different keys. One key can be used to operate the lock clockwise only and the other key to operate the lock counterclockwise only. The function of the lock is based on the principle that the locking disks can move within a limited angle with respect to the cylinder of the lock, that is between two end positions, and that the one key starts its operation movement with the locking disks in one end position and the other key with the locking disks in the opposite end position.

The invention relates to a cylinder lock comprising a stationary cylinder housing, a cylinder turnable therein and enclosing a plurality of locking disks turnable by means of a key of the lock and a locking bar locking the cylinder with respect to the cylinder housing, which locking bar is located between the edges of the locking disks and the stationary cylinder housing and is movable from a locking position into a cylinder-releasing position in a channel formed by recesses in the edge of the locking disks when arranged in a certain position, which look has a key provided with combination surfaces determining the turning angle of the locking disks and with a returning surface working in the oposite direction turning back the locking disks.

For certain special purposes cylinder locks are required which are operated with two different keys of which one can be used only to rotate the cylinder in direction and the other one only to rotate the cylinder in the opposite direction. By using a lock with this function a so-called one-way locked door can be obtained, that is a door which can be opened from one side and locked from its opposite side after which no return through the door using the same key is possible. There are no such locks on the market despite the considerable demand for this type of lock.

The object of the invention is to provide a lock which has the above mentioned characteristics and which is based on known lock types in which only very small modifications have been made. The invention is characterized in that the lock has two diiferent keys of which the combination surfaces compared to each other, and the returning surfaces compared to each other work in opposite turning directions, the combination surfaces on the keys being made so that either one of the keys from its own starting position and its own turning direction is able to turn the locking disks into a cylinder-releasing position.

The locking disks can move only a certain maximum angle with respect to the cylinder. In an ordinary locking disk lock all the locking disks are in their one end position when the key is pushed into the key hole. When the key is turned the combination surfaces turn the locking disks different angles so that the outer recesses of the locking disks form a channel at the locking bar. The locknig disks are then in their cylinder-releasing position. The invention is based on the observation that the said releasing position may be as well reached by starting the turning of the locking disks from their opposite end position if the returning surface and the combination surfaces change place. If it is desired that there is only one recess for the locking bar in each of the locking disks the corresponding combination surfaces of the two keys are made so that the sum of the turning angles they give to the same locking disk is constant and is the same as the maximum turning angle of the locking disks with respect to the cylinder. However, this is not necessary because it is also possible that one or several of the locking disks are provided with two recesses for the locking bar, and in this case the position of the second recess determines the position of the corresponding combination surface of the second key.

For practical reasons it is usually desired that the outermost looking disk, at least at that end of the lock from which the key is pushed into the key hole, preferably also in the opposite end of the lock, is so formed that it moves the maximum angle with respect to the cylinder when the key is turned. In order to obtain that the outermost disks are of this kind with respect to both the keys, these disks have to have two recesses for the locking bar.

In the following description an embodiment of the invention is described with reference to the accompanying drawing in which:

FIG. 1 shows a cross-ection of a lock according to the invention,

FIG. 2 shows a lifting locking disk.

FIG. 3 shows a normal key which is to be used for right hand operation of the lock,

FIG. 4 shows a mirror key which is to be used for left hand operation of the lock, I

FIG. 5 shows a cross-section of a normal key with its combination surfaces, and

FIG. 6 shows the cross-section of a mirror key with its combination surfaces.

In the drawing 10 indicates the stationary cylinder housing of a lock, 11 the rotatable cylinder, 12 the locking disks, 13 the locking bar and 14 the key. The locking disks 12 have a small projection 15 which, when the key 14 is turned from its initial position shown in FIG. 1 to a position releasing the cylinder 11, moves in an opening 19 made in the cylinder 11. The combination value of the shown locking disk is 1, which means that one angle step a has been removed from the combination side of the key. Consequently, the locking disk moves with respect to the cylinder an angle b which is 90-a1 This movement brings the peripheral recess 16 of the locking disk to the position of the locking bar 13. In the shown embodiment this angle step a is one fifth of a right angle, that is 18.

If it is desired that the locking disk 12 moves to the cylinder-releasing position starting from its opposite end position 15', shown in broken lines, in which the recess 16 is at the position 16, the combination surface of the key has to have the combination value 4, which means that four angle steps a have been removed from the right angle combination sector of the key, and hence the key turns the locking disk only one angle step a and the recess of the locking disk moves to the position of the locking bar 13.

From the above example it is evident that the sum of the corresponding combination values of the normal key and the mirror key always has to be the same as the greatest combination value. However, this rule is applicable only if it is desired that there should be only one recess 16 in the locking disks. It is also possible to have two recesses in some of the locking disks. Usually it is desired that in both ends of the key there is a combination surface 0 and in this case the two outermost locking disks of the locking disk set have to be provided with two recesses as shown in FIG. 2. The outermost locking disks usually work as so called lifting disks in which the one side surface 17 of the recess is an obliquely disposed surface lifting the locking bar. Also both side surfaces of a groove 18 made in the cylinder housing for the locking bar are obliquely disposed surfaces lifting the locking bar. The locking bar 13 does not have to be circular. Several other cross-sectional forms may be used as well. The locking bar can be straight or provided with a right angle bent end portion, it may be spring loaded or completely free. A slight outwards directed spring load is advantageous because the locking bar then works as a stopper for the cylinder which makes it easier to remove the key from the lock. At the same time the locking bar gives a small click which indicates that the cylinder is in such a position relative to the cylinder housing, that the locking bar 13 moves into its groove 18.

FIG. 3 shows a side view of a normal key and FIG. 4 a side view of the corresponding mirror image key. These two keys are used to operate a lock in which the outermost locking disks are locking disks of the kind shown in FIG. 2. The combination surfaces of the keys are best shown in FIGS. 5 and 6. The basic form of the key shown is semicylindrical, and the combination surfaces are made by means of removing sector formed portions of different size, starting from one side of the fiat surface of the semi-cylindrical body. However, it should be noted that this key form is not at all the only one possible. Very different basic forms can be used and also a semi-cylindrical key can be transformed by providing it with a ridge, a groove or the like.

The function of a lock according to the invention is the following. The movements of the key are guided motions. When the lock has been operated with the normal key and the mirror key is inserted in the lock, turning in the working direction of the mirror key cannot take part immediately. This is because the parts of the lock do not move in this direction. The key has to be turned first in the opposite direction as far as possible, in the shown embodiment 90". During this movement the locking disks are arranged in a new starting position (with the projections of the disks all moved to the other of the edges of the opening 19 in the cylinder 11) and the lock can now be operated by turning the key in its respective Working direction. The operation is similar when the normal key is used after the use of the mirror key. As the movements are guided no instructions for use are needed, but the function of the lock becomes clear in a natural way.

-A look according to the invention can in every respect function exactly in the same way as a normal locking disk lock. Consequently, also in a lock system with locks according to the invention so called selective systems can be used, that is master key suites, grand master key suites and group suites.

The invention is not limited to the embodiment shown, but several different modifications of the invention are feasible within the scope of the following claims.

We claim:

1. A cylinder lock comprising a stationary cylinder housing, a turnable cylinder mounted in said housing, a plurality of locking disks enclosed in said cylinder, each disk being provided with a central opening which is noncircular at least in part, a pair of 'keys insertable into said lock for turning said locking disks, each key engagign the disk at the non-circular portion of the opening,-

a number of said locking disks each including a peripheral radial projection, said projection and said non-circular central opening having the same angular position rela tive to each other in each locking disk with said projec tion, and a locking bar locking said cylinder with respect to said cylinder housing, said locking bar being located between the peripheral edges of said locking disks and said stationar cylinder housing and being movable from a locking position into a cylinder-releasing position in which said locking bar is received in a channel formed by alignment of recesses provided in the peripheral edges of said locking disks, said keys having combination surfaces determining a turning angle for each of said locking disks and a returning surface for turning said locking disks back to their initial position, said combination surfaces and returning surfaces of the two keys being mirror images to turn the disks in respectievly opposite turning directions, the combination surfaces being made such that either of the keys from its own starting position and in its own turning direction is able to turn the locking disks into a cylinder-releasing position, said cylinder having a cutout in which the projections on the locking disks are movable within a limited angle with respect to the cylinder to provide two end positions for the disks, one key having a respective starting position in which the central openings in the disks are aligned and the disks are in one end position, the other key having a respective starting position in which the central openings in the disks are aligned and the disks are in the other end position, the orientation of said recessess and projections of the disks being such that the starting position of one key is the same as the cylinder releasing position of the other key.

2. A look according to claim 1, in which a number of said locking disks have a single peripheral recess for said locking bar, the corresponding combination surfaces of said two keys for said last mentioned locking disks being shaped with respect to each other so that the sum of the turning angles given by corresponding combination surfaces of the keys to one of said last mentioned locking disks, is constant and the same as the maximum turning angle of the locking disks with respect to said cylinder.

3. A lock according to claim 2, in which a majority of the locking disks of the lock have a single peripheral recess for said locking bar.

4. A lock according to claim 1, in which the outermost locking disk, at least in that end of said lock from which the key of the lock is inserted, is so formed, that during the turning of the key it moves the maximum angle with respect to said cylinder, and that it is provided with two peripheral recesses for said locking bar.

5. A look according to claim 4, in which the outermost locking disk at both ends of the lock is so formed that during the turning of the key it moves maximum angle with respect to said cylinder, and is provided with two recesses for said locking bar.

6. A lock according to claim 4, in which in said peripheral recesses of said outermost locking disk one side surface is obliquely disposed to lift said locking bar.

7. A look according to claim 1, in which said cylinder housing is provided with a groove for said locking, which groove has side surfaces are obliquely disposed to lift said locking bar.

8. A lock according to claim 1, wherein each said key has a basically semi-cylindrical portion to be inserted in said lock, said combination surfaces of each said key being made in said semi-cylindrical portion by means of removing sector formed portions of different size, starting from one side of the flat part of said semi-cylindrical key portion.

References Cited FOREIGN PATENTS 25,305 4/1952 Finland 70366 25,706 12/1952 Finland 70366 ROBERT L. WOLFE, Primary Examiner US. Cl. X.R. 70-3 83, 419 

